WRT54GS will not connect to Internet

My Linksys wireless router was working just fine until just the other day, when I was using it wirelessly on my laptop and my Internet Connection said "Local Access Only." At first, I thought it was an issue with my ISP (Comcast), so I called them and power-cycled the modem, router, and laptop. No dice. When I connected the modem directly to the laptop, however, the Internet worked fine. Even when I ran the Ethernet cord from the modem into the Internet port in the back of my Linksys router and another Ethernet cord from port 1 on the back of the router into my laptop's Ethernet port, I still could not access the Internet. When I wire the modem directly into my router and my router directly into my laptop, I am able to ping the router's IP address in Command Prompt, but I am not even able to ping google.com or linksysbycisco.com or linksys.com. I can access my router's setup page online to check the settings, and I have even updated the firmware in my router successfully. I tried the hard reset (30/30/30), but I still only had a local connection. I don't have a firewall turned on, I do not use any proxies, and all of the lights are coming on on the router as they should. I am running out of options, but I would rather see if there is anything else I can do before I go out and blow another $60 on a router. I've had this one for a couple of years - is that their average shelf life? I would appreciate any help you might be able to provide. Here are the IP configuration settings with the computer directly attached to the modem: